1. Field of the Invention
The present invention relates to an imaging apparatus, and, more particularly, to an imaging apparatus having a media sensor.
2. Description of the Related Art
Media sensors are used to detect the presence or absence of print media, and in some cases, are also used to determine the print media type. One form of a media sensor includes a single light source, such as a light emitting diode (LED), and a light detector, such as a phototransistor. Typically, the light detector is located on the same side of a print media as the light source. During operation, the LED directs light at a predefined angle onto a material surface of the print media, and the surface characteristics of the print media are examined in terms of the amount of light reflected from the surface that is received by the light detector. For example, the presence of the print media is detected based upon a predetermined amount of light reflected from the media to the light detector.
Some media sensors include a pair of light detectors, one of the light detectors being positioned to sense reflected diffuse light and a second detector positioned to sense reflected specular light. Such a sensor may be used, for example, to detect and discriminate between paper media and transparency media.
A media sensor that contacts directly a surface of a print media sheet is known in the art as a contact media sensor. Often, the contact media sensor is spring biased to be in contact with the media surface. Typically, such a contact media sensor includes a skid surface which slides along the surface of a print media sheet as the print media sheet advances in a sheet feed direction. The friction created by the contact of the skid surface of the contact media sensor and the surface of the print media sheet often permanently marks or scuffs the surface of the print media sheet.
What is needed in the art is an imaging apparatus configured to reduce or eliminate the marking or scuffing of a surface of a print media sheet resulting from contact between a media sensor and the surface of the print media sheet.